Hydrangea plant named ‘H217904’

ABSTRACT

A new and distinct cultivar of  Hydrangea  plant named ‘H217904’, characterized by its compact, upright and rounded plant habit; vigorous growth habit and moderate growth rate; freely branching habit with strong, thick and sturdy stems; early and freely flowering habit; semi-lacecap type inflorescences with numerous double-type sterile flowers that are intense red purple in color; and good postproduction longevity.

Botanical designation: Hydrangea macrophylla.

Cultivar denomination: ‘H217904’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofHydrangea plant, botanically known as Hydrangea macrophylla,commercially referred to as a semi-lacecap type Hydrangea andhereinafter referred to by the name ‘H217904’.

The new Hydrangea plant is a product of a planned breeding programconducted by the Inventor in De Kwakel, The Netherlands and Glandorf,Germany. The objective of the breeding program was to create new compactand freely-branching Hydrangea plants with strong sturdy stems, largeinflorescences with numerous double-type sterile flowers, attractivesterile flower color and good postproduction longevity.

The new Hydrangea plant originated from a cross-pollination made by theInventor in March, 2012 in De Kwakel, The Netherlands, of a proprietaryselection of Hydrangea macrophylla identified as code number 10-0195-011not patented, as the female, or seed, parent with a proprietaryselection of Hydrangea macrophylla identified as code number10-0170-098, not patented, as the male, or pollen, parent. The newHydrangea plant was discovered and selected by the Inventor as a singleflowering plant from within the progeny of the stated cross-pollinationin a controlled greenhouse environment in Glandorf, Germany in March,2013.

Asexual reproduction of the new Hydrangea plant by vegetative tipcuttings in a controlled environment in De Kwakel, The Netherlands sinceApril, 2014 has shown that the unique features of this new Hydrangeaplant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Hydrangea have not been observed under all possiblecombinations of environmental conditions and cultural practices. Thephenotype may vary somewhat with variations in environmental conditionssuch as temperature and light intensity without, however, any variancein genotype.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘H217904’. These characteristics incombination distinguish ‘H217904’ as a new and distinct Hydrangea plant:

-   -   1. Compact, upright and flat-top plant habit.    -   2. Vigorous growth habit and moderate growth rate.    -   3. Freely branching habit with strong, thick and sturdy stems.    -   4. Early and freely flowering habit.    -   5. Semi-lacecap type inflorescences with numerous double-type        sterile flowers that are intense red purple in color.    -   6. Good postproduction longevity.

Plants of the new Hydrangea can be compared to plants of the female andmale parent selections. Plants of the new Hydrangea differ primarilyfrom plants of the female and male parent selections in sterile flowerform as sterile flowers of plants of the new Hydrangea are double-typeswith several whorls of sepals whereas sterile flowers of plants of thefemale and male parent selections are single-types with a single whorlof sepals.

Plants of the new Hydrangea can be compared to plants of the Hydrangeamacrophylla ‘H216906’, disclosed in U.S. Plant patent application Ser.No. 15/731,672. In side-by-side comparisons, plants of the new Hydrangeadiffer primarily from plants of ‘H216906’ in the followingcharacteristics:

-   -   1. Plants of the new Hydrangea have semi-lacecap type        inflorescences whereas plants of ‘H216906’ have mophead-type        inflorescences.    -   2. Inflorescences of plants of the new Hydrangea are shorter and        flatter than and not as globular as inflorescences of plants of        ‘H216906’.    -   3. Plants of the new Hydrangea have larger sterile flowers with        larger sepals of plants of ‘H216906’.    -   4. Plants of the new Hydrangea have darker red purple-colored        sterile flower sepals than plants of ‘H216906’.    -   5. Plants of the new Hydrangea and ‘H216906’ differ in reaction        to aluminum sulfate treatment as sterile flower sepals of plants        of the new Hydrangea treated with aluminum sulfate become violet        blue in color whereas sterile flower sepals of plants of        ‘H216906’ treated with aluminum sulfate become light purple in        color.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance ofthe new Hydrangea plant showing the colors as true as it is reasonablypossible to obtain in colored reproductions of this type. Colors in thephotographs may differ from the color values cited in the detailedbotanical description which accurately describe the colors of the newHydrangea plant.

The photograph on the first sheet is a side perspective view of atypical flowering plant of ‘H217904’.

The photograph on the second sheet is a top perspective view of atypical flowering plant of ‘H217904’.

The photograph on the third sheet is a close-up view of a typicaldeveloping inflorescence of ‘H217904’ that has not been “blued”, thatis, treated with aluminum sulfate.

The photograph on the fourth sheet is a close-up view of a typicaldeveloping inflorescence of a plant of ‘H217904’ that has been “blued”.

DETAILED BOTANICAL DESCRIPTION

Plants used in the aforementioned photographs and in the followingdescription were grown during the late spring and early summer in 13-cmcontainers in a glass-covered greenhouse in De Kwakel, The Netherlandsand under cultural practices typical of commercial Hydrangea production.During the production of the plants, day and night temperatures averaged17° C. Plants of the new Hydrangea were one year old when thephotographs and description were taken. Plants of the new Hydrangea canbe successfully treated with aluminum sulfate to “blue” theinflorescences. In the following description, color references are madeto The Royal Horticultural Society Colour Chart, 2015 Edition, exceptwhere general terms of ordinary dictionary significance are used.

-   Botanical description: Hydrangea macrophylla ‘H217904’.-   Parentage:    -   -   Female, or seed, parent.—Proprietary selection of Hydrangea            macrophylla identified as code number 10-0195-011, not            patented.        -   Male, or pollen, parent.—Proprietary selection of Hydrangea            macrophylla identified as code number 10-0170-098, not            patented.-   Propagation:    -   -   Type cutting.—By vegetative tip cuttings.        -   Time to initiate roots, summer.—About two weeks at            temperatures about 23° C.        -   Time to initiate roots, winter.—About 18 days at            temperatures about 20° C.        -   Time to produce a rooted young plant, summer.—About four            weeks at temperatures about 23° C.        -   Time to produce a rooted young plant, winter.—About five            weeks at temperatures about 20° C.        -   Root description.—Thick; typically whitish brown in color,            actual color of the roots is dependent on substrate            composition, water quality, fertilizer type and formulation,            substrate temperature and physiological age of roots.        -   Rooting habit.—Freely branching; dense.-   Plant description:    -   -   Plant and growth habit.—Compact, upright and flat-top plant            habit; strong and sturdy stems; moderate growth rate and            vigorous growth habit.        -   Plant height.—About 30 cm.        -   Plant diameter or area of spread.—About 40 cm to 45 cm.-   Lateral branch description:    -   -   Branching habit.—Freely branching habit; when pinched, about            six to eight lateral branches develop per plant.        -   Length.—About 20 cm to 25 cm.        -   Diameter.—About 4 mm to 5 mm.        -   Internode length.—About 3 cm to 4 cm.        -   Texture.—Smooth, glabrous; fully developed, woody.        -   Aspect.—Upright to about 20° from vertical.        -   Strength.—Strong, sturdy.        -   Color.—When developing: Close to 144C; at internodes, close            to 187B; lenticels, close to 187A. Developed: Close to 144A;            at the internodes, close to 187B; when woody, close to 177C;            lenticels, close to 187A.-   Leaf description:    -   -   Arrangement.—Opposite, simple.        -   Length.—About 7 cm to 8 cm.        -   Width.—About 5 cm to 6 cm.        -   Shape.—Ovate.        -   Apex.—Acute.        -   Base.—Obtuse.        -   Margin.—Serrulate.        -   Texture, upper surface.—Smooth to rugose, glabrous.        -   Texture, lower surface.—Rugose, glabrous.        -   Venation pattern.—Pinnate.        -   Color.—Developing and fully developed leaves, upper surface:            Close to 147A; venation, close to 145B. Developing and fully            developed leaves, lower surface: Close to 137D; venation,            close to 145C.        -   Petioles.—Length: About 1.5 cm to 2 cm. Diameter: About 3 mm            to 4 mm. Texture, upper and lower surfaces: Smooth,            glabrous. Color, upper and lower surfaces: Close to 145B.-   Flower description:    -   -   Flower type and habit.—Double-type sterile flowers arranged            on semi-lacecap type terminal panicles; panicles globular to            flattened in shape; flowers face upright to outwardly            depending on their position in the inflorescence; no fertile            flowers have been observed on plants of the new Hydrangea to            date.        -   Fragrance.—None detected.        -   Natural flowering season.—Early flowering habit, plants            begin flowering about 10 to 15 months after planting;            flowering begins in the early summer and is continuous            throughout the summer in Northern Europe.        -   Flower longevity.—Sterile flowers last about four months on            the plant, sterile flowers persistent.        -   Quantity of flowers.—Freely flowering habit; outer whorl of            flowers, about 20 to 30; total per inflorescence, about 160            to 180 sterile flowers per panicle; to date, no fertile            flowers have been observed on plants of the new Hydrangea.        -   Panicle height.—About 8 cm to 10 cm.        -   Panicle diameter.—About 15 cm to 20 cm.        -   Sterile flower buds.—Length: About 3 mm. Diameter: About            3 mm. Shape: Rounded. Color: Close to 144B.        -   Sterile flower diameter.—About 4 cm by 4.5 cm.        -   Sterile flower depth (height).—About 0.5 cm to 1.5 cm.        -   Petals, sterile flowers.—Petal development has not been            observed on plants of the new Hydrangea to date.        -   Sepals, sterile flowers.—Quantity and arrangement: About 13            to 15 in about three whorls. Length, outer whorl: About            1.5 cm. Width, outer whorl: About 1 cm to 1.5 cm. Length,            inner whorls: About 0.5 cm to 1 cm. Width, inner whorls:            About 0.5 cm to 1 cm. Shape: Rhomboidal. Apex: Acute. Base:            Cuneate. Margin: Entire. Texture, upper and lower surfaces:            Smooth, glabrous. Color: When opening, upper and lower            surfaces: Close to 145C. Fully opened, upper surface: Outer            sepals, close to 67A; when “blued”, close to 96C; colors do            not change with development. Fully opened, lower surface:            Close to 65A; when “blued”, close to 96D; colors do not            change with development.        -   Pedicels, sterile flowers.—Length: About 3 cm to 4 cm.            Diameter: About 2 mm to 3 mm. Strength: Strong. Aspect:            Erect to about 45° from vertical. Texture: Smooth, glabrous.            Color: Close to 65B.        -   Reproductive organs.—To date, reproductive organ development            has not been observed on sterile flowers of plants of the            new Hydrangea; all reproductive organs are “transformed”            into inner whorls of sepals.        -   Fruits and seeds.—Fruit and seed development has not been            observed on plants of the new Hydrangea to date.-   Pathogen & pest resistance: To date, under commercial production    conditions, plants of the new Hydrangea have not been observed to be    resistant to pathogens and pests common to Hydrangea plants.-   Temperature tolerance: Plants of the new Hydrangea have been shown    to be tolerant to temperatures ranging from about 3° C. to about 38°    C.

It is claimed:
 1. A new and distinct Hydrangea plant named ‘H217904’ asillustrated and described.